n-Alkyl Methacrylate Polymeric Memristors for Synaptic Response Modeling: Organic and Biologically Relevant Thin Films

There is a strong interest in organic materials for electrical devices due to several advantages that organic systems have over their inorganic counterparts including ease of processability and lower toxicity. Many of these organic materials can be utilized in the creation of thin-film devices that can be formed in high-throughput processes and with a very small profile. One such device that has emerged in recent years is the memristor which can be used in new computational concept or as a synaptic model. This work studies the alternating current (AC) and direct current (DC) electrical response of a number n-alkyl methacrylate polymers with a charge transporting pendant carbazole ring. The electrical properties of the polymers were studied as a function of n-alkyl length with n ranging from 2 to 11. The DC current (I)-voltage (V) response of the polymers was characterized by an erratic and bistable response, while their AC I-V response was a pinched hysteresis loop when measured between 1-100 Hz. For polymers with n \u3c 9, their pinched hysteresis loop is characterized by jump transitions indicative of bistability, while polymers with n ≥ 9 had a pinched hysteresis loop that is smooth in appearance. Dielectric spectroscopy on the polymers indicates that as the n-alkyl length is increased, the rotation flexibility of the carbazole moiety is enhanced. The n-alkyl methacrylate polymers with a pendant carbazole ring spaced n ≥ 9 exhibited a lower activation energy and temperature for the onset of ring motion and resulted in polymer-based memristors that exhibit electrical characteristics, such as incrementally adjustable conductivity, that are potential candidates for mimicking synaptic plasticity. Further characterization was done on similar methacrylate systems with oxygen-substituted side chains and the addition of bulky phenyl groups to the carbazole moieties. From this work, the most promising candidate for synaptic modeling behavior was taken and further examined. It was shown that this polymer could be pulsed through a multitude of conductivity states and demonstrated behavior consistent with the Hebbian Learning Rule upon the application of pre- and post-synaptic pulses. The system was further characterized for the effects of different spike rates and voltages before being utilized in a flexible device. Other thin-film devices as well as novel processing methods were also demonstrated in this work including a biologically based reserve battery and a printed diode utilizing pentacene. The battery utilized standard alkaline chemistry where the zinc and manganese oxide electrodes are formed using stencil printing. Fish eggs are used to sequester the electrolyte out of the system until the application of force to the device. This application of force bursts the fish eggs and allows the battery to function by introducing the electrolyte into the system. A printed diode is also demonstrated through the use of a miniemulsion process that allows for the dispersion of the material into aqueous solution. This pentacene emulsion in water can then be used as the basis for the formation of diodes in a variety of fabrication processes

Identification, Bioassay-guided Isolation & Pharmacological Properties of an Antidiabetic Active Compound(s) from Traditional Medicinal Plants

Recent trends in diabetes treatments show an increasing interest in traditional systems of medicine. Ayurveda, a traditional Indian system medicine, advocates a wide range of medicinal plants to treat diabetes. Although there have been numerous studies on extracts from these medicinal plants that demonstrate antidiabetic activity, scientific studies directed to the isolation, purification and identification of active ingredients responsible for the hypoglycemic activity and also the modes of action of these extracts/active ingredient(s) on glucose homeostasis have been often inconclusive or lacking except for a few cases. The aim of this present study was to identify and isolate a potent antidiabetic compound(s) from some extensively advocated Ayurvedic antidiabetic plants such as 'Trigonella foenum-graecum' Linn (TFG), 'Pterocarpus marsupium' Roxb (PM), 'Gymnema sylvestre' R.Br (GS) and 'Curcuma longa' Linn (CL). An in-house developed 'in vitro' tissue culture-based bioassay method was employed in the present study to determine the effects of plant extracts on insulin secretion from mouse pancreas tissues and on glucose uptake by mouse skeletal muscle tissues under both normoglycemic (5mM glucose) and hyperglycemic (12mM glucose) culture conditions. The results from our preliminary study indicated that all these plant extracts have beneficial effects on glucose homeostasis either by stimulating insulin or enhancing glucose uptake or activating both. In terms of their comparative effects on tissues that regulate glucose metabolism, the aqueous extracts of plants, PM and CL, were found to be more potent when compared with other studied aqueous extracts of plants TFG and and GS, within culture conditions

Investigation of the Climatic and Environmental Context of Hendra Virus Spillover Events 1994–2010

Hendra virus is a recently emerged bat-borne zoonotic agent with high lethality in horses and humans in Australia. This is a rare disease and the determinants of bat to horse transmission, including the factors that bring these hosts together at critical times, are poorly understood. In this cross-disciplinary study climatic and vegetation primary productivity variables are compared for the dispersed and heterogenic 1994–2010 outbreak sites. The significant occurrence of spillover events within the dry season (p =  0.013, 95% CI (0.57–0.98)) suggests seasonal forcing of transmission across species, or seasonal forcing of virus excretion by the reservoir host. We explore the evidence for both. Preliminary investigations of the spatial determinants of Hendra disease locations are also presented. We find that postal areas in the Australian state of Queensland in which pteropid fruit bat (flying fox) roosts occur are approximately forty times more likely (OR = 40.5, (95% CI (5.16, 317.52)) to be the location of Hendra spillover events. This appears to be independent of density of horses at these locations. We consider issues of scale of host resource use, land use change and limitations of existing data that challenge analysis and limit further conclusive outcomes. This investigation of a broad range of potential climatic and environmental influences provides a good base for future investigations. Further understanding of cross-species Hendra virus transmission requires better understanding of flying fox resource use in the urban-rural landscape

Psychiatric diagnoses, trauma, and suicidiality

BACKGROUND: This study aimed to examine the associations between psychiatric diagnoses, trauma and suicidiality in psychiatric patients at intake. METHODS: During two months, all consecutive patients (n = 139) in a psychiatric hospital in Western Norway were interviewed (response rate 72%). RESULTS: Ninety-one percent had been exposed to at least one trauma; 69 percent had been repeatedly exposed to trauma for longer periods of time. Only 7% acquired a PTSD diagnosis. The comorbidity of PTSD and other psychiatric diagnoses were 78%. A number of diagnoses were associated with specific traumas. Sixty-seven percent of the patients reported suicidal thoughts in the month prior to intake; thirty-one percent had attempted suicide in the preceding week. Suicidal ideation, self-harming behaviour, and suicide attempts were associated with specific traumas. CONCLUSION: Traumatised patients appear to be under- or misdiagnosed which could have an impact on the efficiency of treatment

Crossing the Border: Molecular Control of Motor Axon Exit

Living organisms heavily rely on the function of motor circuits for their survival and for adapting to ever-changing environments. Unique among central nervous system (CNS) neurons, motor neurons (MNs) project their axons out of the CNS. Once in the periphery, motor axons navigate along highly stereotyped trajectories, often at considerable distances from their cell bodies, to innervate appropriate muscle targets. A key decision made by pathfinding motor axons is whether to exit the CNS through dorsal or ventral motor exit points (MEPs). In contrast to the major advances made in understanding the mechanisms that regulate the specification of MN subtypes and the innervation of limb muscles, remarkably little is known about how MN axons project out of the CNS. Nevertheless, a limited number of studies, mainly in Drosophila, have identified transcription factors, and in some cases candidate downstream effector molecules, that are required for motor axons to exit the spinal cord. Notably, specialized neural crest cell derivatives, referred to as Boundary Cap (BC) cells, pre-figure and demarcate MEPs in vertebrates. Surprisingly, however, BC cells are not required for MN axon exit, but rather restrict MN cell bodies from ectopically migrating along their axons out of the CNS. Here, we describe the small set of studies that have addressed motor axon exit in Drosophila and vertebrates, and discuss our fragmentary knowledge of the mechanisms, which guide motor axons out of the CNS

Social and occupational factors associated with psychological distress and disorder among disaster responders: a systematic review

BACKGROUND: When disasters occur, there are many different occupational groups involved in rescue, recovery and support efforts. This study aimed to conduct a systematic literature review to identify social and occupational factors affecting the psychological impact of disasters on responders. METHODS: Four electronic literature databases (MEDLINE®, Embase, PsycINFO® and Web of Science) were searched and hand searches of reference lists were carried out. Papers were screened against specific inclusion criteria (e.g. published in peer-reviewed journal in English; included a quantitative measure of wellbeing; participants were disaster responders). Data was extracted from relevant papers and thematic analysis was used to develop a list of key factors affecting the wellbeing of disaster responders. RESULTS: Eighteen thousand five papers were found and 111 included in the review. The psychological impact of disasters on responders appeared associated with pre-disaster factors (occupational factors; specialised training and preparedness; life events and health), during-disaster factors (exposure; duration on site and arrival time; emotional involvement; peri-traumatic distress/dissociation; role-related stressors; perceptions of safety, threat and risk; harm to self or close others; social support; professional support) and post-disaster factors (professional support; impact on life; life events; media; coping strategies). CONCLUSIONS: There are steps that can be taken at all stages of a disaster (before, during and after) which may minimise risks to responders and enhance resilience. Preparedness (for the demands of the role and the potential psychological impact) and support (particularly from the organisation) are essential. The findings of this review could potentially be used to develop training workshops for professionals involved in disaster response. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40359-016-0120-9) contains supplementary material, which is available to authorized users

Attitudes and burden in relatives of patients with schizophrenia in a middle income country

BACKGROUND: Most studies of family attitudes and burden have been conducted in developed countries. Thus it is important to test the generalizability of this research in other contexts where social conditions and extended family involvement may be different. The aim of this study was to assess the relationship between the attitudes of caregivers and the burden they experience in such a context, namely Arica, a town located in the northernmost region of Chile, close to the border with Peru and Bolivia. METHODS: We assessed attitudes towards schizophrenia (including affective, cognitive and behavioural components) and burden (including subjective distress, rejection and competence) in 41 main caregivers of patients with schizophrenia, all of whom were users of Public Mental Health Services in Arica. RESULTS: Attitude measures differed significantly according to socio-demographic variables, with parents (mainly mothers) exhibiting a more negative attitude towards the environment than the rest of the family (t = 4.04; p = 0.000).This was also the case for caregivers with a low educational level (t = 3.27; p < 0.003), for the oldest caregivers (r = 0.546; p = 0.000) and for those who had spent more time with the patient (r = 0.377; p = 0.015). Although attitudes had significant association with burden, their explanatory power was modest (R2 = .104, F = 4,55; p = .039). CONCLUSIONS: Similar to finding developed countries, the current study revealed a positive and significant relationship between the attitudes of caregivers and their burden. These findings emphasize the need to support the families of patients with schizophrenia in this social context

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p